Many image forming apparatuses, such as printers and copiers, utilize one or more input trays for holding stacks of media sheets. A sheet feeding mechanism is typically mounted in the tray or in the housing of the image forming apparatus to separate and deliver individual media sheets from the media stack to a media path in the image forming apparatus. One known type of input tray takes the form of a rectangular bin having a slanted wall at the media output end. A known sheet feeding mechanism for this type of tray includes a support arm coupled to a power-driven pickup roller that rests on the stack of media sheets. When the pickup roller is activated, it acts by friction to push individual sheets laterally against and upwardly the slanted wall. Different drive motors and/or many unique parts, e.g. gears, belts, pulleys, swing arms, are often required to move the sheet delivery mechanism into a correct engaging position with the media stack and to drive the pickup roller.
Another type of input tray is a high-capacity input tray, which is capable of storing high volume of media, e.g. 2000 sheets or more. High-capacity input trays are used in order to reduce the amount of downtime due to reloading of the input trays. Normally, the media sheets are stacked on a lifting tray that displaces vertically as media sheets are removed from the stack by a sheet feeding mechanism. Two different motors are required for this type of high-capacity input tray: one to move the lifting tray and one to drive the sheet feeding mechanism. The above conventional designs for sheet delivery are complicated and costly to implement.
There exists a need for a media input system with a sheet delivery mechanism that does not require multiple drive motors or unique parts to operate, that is simple to implement and can be installed at a relatively low cost.